Lipids of virus infected cells. II. Lipid analysis of HeLa cells infected with vaccinia virus

Metabolomics of Rhabdomyosarcoma Cell During Echovirus 30 Infection

Background

Echovirus 30 (E30) causes acute aseptic meningitis. Viral replication requires energy and macromolecular precursors derived from the metabolic network of the host cell. The effect of viral infection within a host cell metabolic activity remains unclear.

Methods

To gain an insight into cell-virus interaction during E30 infection we used a human rhabdomyosarcoma cell line. In a new approach to metabolomics, ^1H NMR was used to measure the level of various cellular metabolites at different times of infection and morphological examination of the cells. Statistical analysis was done by using Confidence interval (CI) 95% and One-way ANOVA test.

Results

The¹H NMR metabolite spectrum signals were observed between mock infected and virus infected cells. Both mock infected and virus infected cells utilized glucose through metabolic pathways and released metabolic end products. Upon infection, the concentration of Alanine, Lactate, Acetate, Glutamate, Tyrosine, Histidine, Phenylalanine, Creatine, Choline and Formate, increased. Interestingly, all of these augmented metabolites were decreased during later stage of infection. The cells showed wide-ranging lipid signals at the end of infection, which correlates with the morphological changes as apoptosis (programmed cell death) of cells was observed. A significant association was found between time interval (12 h, 24 h, and 48 h) and metabolites likewise Alanin, Lactate, Acetate, Glutamate, Tyrosine, Histidine, Phenylalanine, Creatine, Choline and Formate respectively released by cell during infection, which is highly significant (p < 0.01).

Conclusion

Progressive breakdown and utilization of all cellular components were observed as the infection increased. This study is useful for monitoring the cellular metabolic changes during viral infection.

Permeability changes of plasma and lysosomal membranes in HeLa cells infected with rabbit poxvirus

Infection of HeLa-cell monolayer cultures with rabbit poxvirus induces a marked decrease in cell-associated protein and in the activities of lactate dehydrogenase, acid phosphatase, and beta-glucuronidase. This effect begins to occur around 10 hours post-infection (p.i.) and is accompanied by a concomitant rise of these enzyme activities in the culture medium. Only few cells detach from infected monolayers and these cannot account for protein release. Virion release can be inhibited at 4 degrees C, whereas protein release cannot and it seems therefore that these events do not happen by a common mechanism. Moreover, penetration studies with [14C]-sucrose indicate that protein release reflects a true increase in plasma membrane permeability. Using the Gomori stain for acid phosphatase, a release of the enzyme into the cytoplasm around 8 hours p.i. can be confirmed rendering a causative role of lysosomal hydrolases in the pathogenesis of the observed plasma membrane permeability changes possible but not proving it.